The present invention generally relates to a storage control apparatus to which Thin Provisioning is applied.
In the case in which a host computer recognizes a logical volume in a first storage apparatus and writes the data to the logical volume, a second storage apparatus is used as substitute for the first storage apparatus as a write destination of the data from the host computer. In this case, it is necessary that the data is moved from the first storage apparatus to the second storage apparatus.
The storage apparatus to which Thin Provisioning (also referred to as Dynamic Provisioning) is applied is publicly known (see Patent Literature 1). The storage apparatus of this type is provided with a virtual logical volume (hereafter referred to as a virtual VOL) that is configured by a plurality of virtual pages (virtual storage areas) and a pool that is configured by a plurality of pool VOLs in general. The pool VOL is a logical volume that is made to be a member of a pool and is configured by at least two real pages (substantive storage areas). In the case in which the storage apparatus writes data to a virtual page and a virtual page of a write destination is an unallocated virtual page, the storage apparatus allocates a real page to the virtual page from a pool and writes the data of a write target to the allocated real page. In the case in which the data is moved from the first storage apparatus to the second storage apparatus, it is thought that the data is moved from a logical volume in the first storage apparatus to a virtual VOL in the second storage apparatus for instance. Moreover, the technology for moving the data in a unit of a page to other storage medium is also disclosed (see Patent Literature 2).    Patent Literature 1: Japanese Patent Application Laid-Open Publication No. 2005-234820    Patent Literature 2: Japanese Patent Application Laid-Open Publication No. 2005-301627